The present invention pertains to a device for cutting and restraining a chain of stitches in sewing machines having two or more needles so as to effect incorporation of this chain into the following seam of stitches. To incorporate the length of a chain of stitches formed after completion of a preceding seam into the following seam, it is necessary that the entire length which was formed be manipulated so that it is aligned with the sewing axis.
Prior to the instant invention chains formed by a single series of stitches, i.e., each chain is formed by a single needle, have been aligned with the sewing axis by manipulating them individually or combining separate chains as is done when forming so-called safety seams.
With reference to forming safety seams, the known types of cutting and retaining devices utilized have a needle plate with a needle hole arranged to effect a series of straight stitches and a throat portion with an associated tongue with which a needle cooperates to form a series of whipped or overlocked stitches. This needle plate also includes a transverse slot which interconnects the needle hole with the throat in an area disposed forwardly of the needle and serves as a means whereby the chain of straight stitchs can be moved from the needle hole to the throat to be with the chain of whipped stitches at the appropriate time when they should be cut and held in alignment with the sewing axis in readiness for the next seaming cycle.
This transverse slot is located forwardly of the needles in order to facilitate complete removal of the chain from the tongue and the necessary relocating of each of the chains with respect to their stitching instrumentalities. Prior to the instant invention there was no desirable means for manipulating the chains of whipped or overlocking stitches which are formed utilizing a plurality of needles such, for example, of those formed by stitches of type 514 according to the American Federal Standard Catalog, wherein the stitches produced by each needle are linked together by a transverse or covering thread. The needle plate provided in sewing machines utilized for the formation of the above type of stitches has, as is well known, at least two throats for the needles disposed in side by side relation and include an equal number of cooperating tongues. These throats are open and communicate with each other in the area where the stitches leave their respective tongues which is located downstream of the stitching instrumentalities. For this reason, it has not been possible upon completion of a seam to utilize known devices, for incorporating a length of chain remaining free on the sewing machine into the next seam.
An object of the present invention is that of providing an improved needle plate having means which facilitates the grouping together of the threads forming the chain that is to be incorporated in the next seam, and to group said threads within the right hand needle throat after having removed them from their respective tongues.
The needle plate according to the invention is characterized by a deflecting means for the threads forming the chains and forms an integral part thereof located downstream of the throats for the needles. This deflecting means is spaced from the needle throats and oriented so as to extend transversly relative to the longitudinal lengths of the latter and is effective in grouping all the threads together prior to their entering the throat for the right hand needle. This operation is accomplished by a single working procedure which may be manual or automatic for removing the thread from their respective tongues and then shifting them together to a position whereat they are cut and held by known devices in alignment with the sewing axis.
The main advantage provided by the present invention is that of providing a means whereby the threads forming chains which are interconnected with the needle or needles to the left of the right hand needle can be readily grouped together and aligned forwardly of the stitching instrumentalities and then be incorporated in the seam which follows in the desired manner. This operating step can be accomplished manually without any complicated or involved procedures on the part of the operator for all that is required is to lightly pull the workpiece in the direction of its normal advance and then turn or rotate it about the needle.
During the manual step of pulling the workpiece, the deflecting means is effective in engaging the threads and grouping them together in the area downsteam of the right hand needle throat and when the workpiece is rotated, it causes all of said threads to enter the right hand needle throat.
A further characteristic of the invention is that the deflecting means defines a transverse projection forming a part of the needle plate and extends across the area adjacent to each needle throat and terminates substantially in line with the tongue of the right hand needle throat. This transverse projection has both its side surfaces tapered towards its point and is spaced from the tongues so as to form an abutment for engaging the threads removed from said tongues in order to deflect them to a position where they will be grouped together prior to entering the throat for the right hand needle.
Other objects and advantages of the present invention will become more fully apparent by reference to the appended claims and as the following detailed description proceeds in reference to the figures of drawing wherein: